<?php
header('Content-Type:image/png');
$img = imagecreatefrompng('415.png');
$captcha = imagecreatefrompng('captcha.png');
//imagecopy($img,$captcha,0,0,0,0,imagesx($captcha),imagesy($captcha));
#最后一个标识透明度
imagecopymerge ($img,$captcha,0,0,0,0,imagesx($captcha),imagesy($captcha),50);
imagepng($img);
